Jump to content

Search the Community

Showing results for tags 'rbe3'.



More search options

  • Search By Tags

    Type tags separated by commas.
  • Search By Author

Content Type


Forums

  • Altair Support Forum
    • Welcome to Altair Support Forum
    • Installation and Licensing
    • Modeling & Visualisation
    • Solvers & Optimization
    • Multi Body Simulation
    • Conceptual design and Industrial design
    • Model-Based Development
    • Manufacturing Simulation
    • CAE Process Automation
  • Academic Partner Alliance Forum
    • APA - Composites
    • APA - CFD & Thermal
    • APA - Vehicle Dynamics
    • APA - Manufacturing
    • APA - Crash and Safety
    • APA - Noise, Vibration and Harshness
    • APA - System Level Design
    • APA - Structural and Fatigue
    • APA - Marine
    • APA - Optical Design
  • Japanユーザーフォーラム
    • ユーザーフォーラムへようこそ
    • Altair製品の意外な活用例
    • インストールとライセンス
    • モデリング(プリプロセッシング)
    • シミュレーション技術(ソルバー)
    • データ可視化(ポストプロセッシング)
    • モデルベース開発
    • コンセプト設計と工業デザイン
    • 製造シミュレーション
    • CAE プロセスの自動化
    • 学生向け無償版
    • エンタープライズソリューション

Categories

There are no results to display.


Find results in...

Find results that contain...


Date Created

  • Start

    End


Last Updated

  • Start

    End


Filter by number of...

Joined

  • Start

    End


Group


AIM


MSN


Website URL


ICQ


Yahoo


Jabber


Skype


Interests


Organization

Found 19 results

  1. In my model, I am attempting to use RBE3 elements as supports to avoid artificial rigidity imposed by RBE2s. Because a support cannot be attached directly to an RBE3 element, I am trying to create a zero length CBUSH element with high stiffness, as suggested in this help document. However, since the CBUSH element is a spring that requires two nodes to be specified, I don't understand how to achieve zero length without selecting the same node for the ends (which gives the error "The independent and the dependent nodes are the same"). This post indicates that it is possible to create coincident nodes, but when I attempted to create a temp node at the same location as the center of my RBE3 (Geometry -> nodes -> x,y,z), it fails to create a distinct node that I can select in the spring creation panel. My questions are: Is it possible to create coincident nodes? If so, how is this done? If not, how do I create a zero length CBUSH element?
  2. Hello all, I am attempting to use some RBE3 elements to apply loads and I am receiving this error: A fatal error has been detected during input processing: *** ERROR # 774 *** When a grid's component has no stiffness, then that component cannot be an independent d.o.f. in an RBE3. RBE3 id = 270584 grid id = 326669 weighted components = 123 max d.o.f with stiff = 1 Would greatly appreciate some advice regarding this. Thanks
  3. Hi, I have different load cases applied at the same location, my problem is that i have to put different independent nodes from a same dependent note, 1 Case for a Z load 1 Case for a Y load 1 case for a X load Foe each case, the load will be applied on the same dependent node, but due to geometrie, the independent nodes will be different, i try to duplicate the node, but i can choose the node to take and apply the 2nd or 3rd load cases.
  4. Hello, I want to model a suspension using 1D-Elements. CROD are used to model the rods from the chassis to the wheel carrier. They are connected to the chassis using RBE3 with dof123 constrained to allow for free rotation. The problem is with the connection to and modeling of the wheel carrier. The rods need to be able to rotate freely around the connection points to the wheel carrier as well. I know about BEAM-Elements but as far as I know they only allow for free rotation around 1 axis. ROD- elements shouldnt constrain the rotations either, but they added stiffness to the model compared to the last option, a simple RBE2 with dof 123 from the end points of the rod to the wheel center as a central node. This setup with an RBE2 with dof123 as a wheelcarrier works good in analysis, but in freeesize I randomly get the error " *** ERROR # 153 *** Exactly zero pivoting encountered during Numerical Factorization; the model may have rigid body mode. " - My question are as follows: Why dont rods work as intended? They shouldnt constrain rotation as far as i know - Why does the rbe2 lead to that error? in analysis the flow of force makes sense and no anomalies appear, sometime the freesize even completes without any problem at all. - do you know of any way to model freely rotatable 1D-elements aside from the options above? Below is a picture of the model:
  5. Hello, I am working on a model in hypermesh where the loads are applied at a single dependent node and transferred to multiple independent nodes. I would like the RBE3 weighting factor to change between groups of nodes. Can I assign different weighting factors to different independent nodes in a single RBE3 element? If not, how can I apply my loads? I have tried using multiple RBE3 elements (one for each weighting factor) except I get the following error (Node 189285 is the node where the loads are applied) *** ERROR # 173 *** A dependent d.o.f. defined more than once in rigid element entry. GRID ID = 189285 component = 1 Thanks, Malcolm
  6. Hi, I have a passenger seat with passenger mass distributed on the seat cushion through RBE element. I am doing a static analysis of the same under 1 g braking and 1 g cornering load condition. The seat is fixed at the bottom. Gravity load is applied in lateral and longitudinal directions. In real scenario if this condition happens the passenger will come out of seat and the same happens on using rbe 3 with displacement of dependent node but not the independent nodes as they are attached to structure. While making rbe3 dof of dependent node is kept fixed in all directions but still it moves? Please clarify on this .
  7. What is difference between RBEs and CE_STRUCT in Hypermesh. Can I use RBE3 instead of CE_STRUCT ?
  8. Hello Everyone, I have been trying since very long on this problem but couldn't find a proper solution. I am experimenting on simple models to see whether the load between the shell and solid is transferred correctly or not. I have considered following three cases: A plate (100 mm * 100 mm * 8 mm) modeled completely with hex elements Same plate modeled completely with shell elements Half of the plate modeled with hex elements (from fixed end) And remaining half with shell elements The actual problem is the 3rd case, and to verify it's results, 1st two cases are being studied. I have tried different approaches (such as with skin elements, tie contact, penetration) but the answers were not matching with the 1st two cases. [The max. von mises stress in the 1st case =5.2e-1 MPa , and max. displacement in 1st case = 1.43e-2 mm ] The plate is fixed with a cantilever support and the force is applied at the free end (shown in the attached force - time graph ) Anybody please get me solved the .hm file attached herewith in the radioss solver. I also want to solve and test the results using RBE2 and RBE3 elements, but I don't know how to use them at the join between 2D and 3D mesh in my case. It would be of great help if the use of RBE2 and RBE3 would be demonstrated. ScaledUp_2D-3D_8mm.hm
  9. Hello everybody, is it possible to create pre-loaded CBUSH elements in Optistruct? I would like to model with spring elements braced components (tet-meshed) with a defined spring stiffness. The spring elements are attached by RBE3 to the component's surfaces (RBE3-spider -- CBUSH -- RBE3-spider). My goal is to model pre-loaded human ligaments restraining the hip. I'd be glad to get any advice on this topic. Best regards Jo
  10. What is difference between Constraining nodes(directly from analysis->constraints) vs. rbe3? I am trying to do tensile test using Ls-dyna solver. Please post your comments.
  11. Hi, I am trying to optimize the design of a control arm of suspension system. For that reason i have modeled the design in NX and exported in IGES format for HW-Hypermesh. Now for my optimization i am concerned with topology optimization of the yellow(design region) part of the arm. The green (non design) region is not to be optimized as per my design requirements. I used the organize command to move the design volume to design component and other to non design component, but while creating a mesh i am having issues. When i mesh the non design region using 2D mesh it got successful (non design mesh.png) after that i make design component as current and mesh it volume tetra mesh 3D, but it is meshing the complete part including nondesign space (design space mesh.png) Kindly check the issue.png about what i am saying. Please assist me in solving it and also once the meshing is done how to combine the design mesh and non design mesh so as in analysis and optimization it should behave as a single unit? The .hm file can be accessed from this link( https://www.dropbox.com/s/pujyaajiumo6zx9/suspension_arm.hm?dl=0) Thank you
  12. Hello, I am trying create rbe3 elems using TCL *createmark nodes 1 101 102 103 104 105 106 *createarray 6 123 123 123 123 123 123 *createdoublearray 6 1.23 1.23 1.23 1.23 1.23 1.23 *rbe3 1 1 6 1 6 100 123456 1.23 In this, How do I calculate weight factor which is in *createdoublearray?
  13. Hi guys, can someone say me what are the properties of the different connectors. Or give me a link where they are discribed, sadly i found nothing in the Help or web.
  14. Hi, is there any problem in using rbe 3 and rwall in the same model? The system having shell elements, rbe 3 , rbe 2 etc. ,is not facing any impact with rwall. and just goes oninto it without energy absorption. Kindly let me know about this.
  15. I am using the function sewing tools function from Aerospace module. I have a doubt. How can I verify whether all the GFEM are attached to DFEM? via RBE3. Thanks.
  16. Hello everybody, " my name is Dean and i have a Problem with RBE 3. Doing the check-analysis I am getting always the error # 173 saying that " A dependent d.o.f. defined more than once in rigid element entry. GRID ID = 214823 component = 1" I have checked the elements for dependency and the browser tells me, that there are no elements with double dependency. Besides I tried to delete the node, but the error is the same. I as well checked for the node with the find function, with the result, that the centre point of the rbe3 element was meant. I would be very thankful if somebody could help me, because I am pretty stuck with this and need help pretty urgently. Kind regards and thank you for your help in advance Dean
  17. Hi All, I am trying to run an analysis on a pipe section subjected to torsion. When I run the analysis I get the below message ***There were 4 error messages during input processing*** The first message is repeated below: *** ERROR # 772 *** It is invalid to use a free grid as an independent grid in RBE3 data. Free spiders are not allowed to be independent grids in RBE3 data. RBE3 id = 4903 free grid id = 9634 weighted components = 123 You should remove this grid from the RBE3 data. *** Run terminated because of error(s) in the input data. Does anyone have any advice to resolve this error? Thanks in advance, Luke
  18. Hello, If I am to put RBE3 in a hole (with no force or constraint attached to the dependant node) will this imply any stiffness to the voids outer surface where the independent nodes are? Or does the hole just remain as it would if it was a void with nothing in it? What type of 1D element could be used to provide a defined stiffness to the outer surface of a hole? Thank you in advance
  19. Hello all, I am trying to create rbe3 element with 1.0 weight to independent nodes , however, following code generates 0.0 weight for independent nodes. my tcl code is ; ################################################################## *createmark nodes 1 "by sphere" -341.255 -75.946 6.482 0.25 inside 1 all 0 *appendmark nodes 1 "by face" set rbl [hm_getmark nodes 1] set nrbl [llength $rbl] for {set i 0} {$i < $nrbl} {incr i 1} { lappend dofl 123456 } *createarray $nrbl [puts $dofl] for {set i 0} {$i < $nrbl} {incr i 1} { lappend wgh1 1.500000 } *createdoublearray $nrbl [puts $wgh1] *createnode -341.761 9.994e-02 1.549 0 0 0 *createmark nodes 2 "by sphere" -341.761 9.994e-02 1.549 0.2 inside 1 all 0 *rbe3 1 1 $nrbl 1 $nrbl [hm_getmark nodes 2] 123456 0 ######################################################################## At the end of the day, I want to generate following RBE3;
×
×
  • Create New...